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Curcumin is a natural polyphenol obtained from Curcuma longa which has gained much attention in medical and scientific fields and is known for its wide range of therapeutic applications. But the natural herb mixtures with high subatomic sizes have low retention limits which does not permit the restorative medication to cross the lipid membranes, subsequently bringing about low bioavailability with confined proficiency. Nanobiotechnology has overcome the drawbacks of curcumin delivery to its targeted site through the use of antioxidant-rich, biodegradable SLNs as drug delivery vehicle with specificity and expanded bioavailability that will encourage the dynamic release of therapeutic ingredients into the body. Herein, optimized curcumin-loaded SLNs (CuSLNs) were developed. The morphological analysis of SEM has shown the average particle size was found to be in the range of 71–112 nm. The physicochemical characteristics of optimized CuSLNs were particle size of 106 nm, zeta potential of − 54 mV, polydispersity index of 0.429 which have confirmed the nanoparticle stability. The FTIR, DSC, and XRD results have suggested the lipids are compatible and confirmed the complete solubilization of curcumin in the lipid phase. Encapsulation efficiency and drug loading capacity of optimized formulation were 88.22 and 13.13, respectively. In vitro release studies have shown the controlled drug release rate of 88% compared with free curcumin and 81% of in vitro antioxidant activity which is compared with the ascorbic acid. The studies confirmed that the formulation of CuSLNs is a promising drug delivery system with controlled drug release, improved bioavailability with good stability.

Nd 3+ /Ho 3+ co-doped SiO 2 -Al 2 O 3 -Na 2 CO 3 -SrF 2 -CaF 2 -Ho 2 O 3 -Nd 2 O 3 oxyfluorosilicate glasses have been prepared by high temperature melt-quenching method. The co-doped samples exhibit fluorescence bands centered at 892, 1058, 1330 nm and 2.0 μm under the excitation of 808 nm laser diode (LD). The energy transfer mechanism between Nd 3+ and Ho 3+ was analyzed based on the absorption, emission and the energy level structures of Nd 3+ and Ho 3+ ions. In the present investigation, the energy transfer efficiency from Nd 3+ to Ho 3+ reached ∼50% under the excitation of 808 nm. This result indicates that Nd 3+ ions can be potentially used as sensitizers for Ho 3+ ions to stimulate the NIR emissions. Stimulated emission cross-section was evaluated for the prominent 5 I 7 → 5 I 8 transition of Ho 3+ ion by using the Mc-Cumber theory. The spectroscopic characteristics of Nd 3+ /Ho 3+ co-doped oxyfluorosilicate glasses are found to be suitable as optical medium for mid infrared emission at ∼2.0 μm.

The fluorescence and upconversion studies of Er3+ doped and Er3+/Nd3+ co-doped silicate based oxyfluoride glasses have been systematically analyzed. The broad band NIR emissions (830–1700 nm), includes optical bands like O, E, S, C and L were observed in the Er3+-Nd3+ co-doped glasses. The NIR emission intensity peaks centered at 876, 1057, 1329 and 1534 nm were observed for the Er3+-Nd3+ co-doped glasses. In the co-doped samples the strongest emission intensity at 1534 nm increased up to 0.5 mol % and then decreased to 3.0 mol % of Nd3+ ions under the excitation of 980 nm. The upconversion studies of the co-doped samples were recorded under the excitation of 980 and 808 nm and found the upconversion emission peaks centered at 524, 530, 547, 590 and 656 nm. The energy transfer processes between the relevant excitation levels of Er3+ and Nd3+ ions and energy transfer efficiency were discussed. The obtained results indicate that Nd3+ can be an efficient sensitizer for Er3+ to enhance upconversion emission at green laser transition for sensors and NIR emission at 1534 nm for optical communication applications.

Highly bioavailable plant phospholipid complex that can reverse aluminum maltolate (AlM)-induced toxicity is not yet reported. Hence, the present study was planned to investigate the impact of oxidative stress and apoptotic changes provoked by Al and ameliorative role of Bacopa phospholipid complex (BPC) in albino rats. The levels of antioxidant enzymes such as superoxide dismutase (SOD), catalase activity (CAT), glutathione peroxidase (GPx), and thiobarbituric acid-reactive substance (TBA-RS) were measured and immunohistochemistry analysis of apoptotic markers, Bax and Bcl-2, was done from the four brain regions such as the hippocampus, cerebral cortex, cerebellum, and medulla oblongata. The levels of antioxidant enzymes and apoptotic markers that were decreased on AlM induction showed a significant increase in their levels, almost as observed in the control, when treated with BPC and Bm. Our results indicate that both BPC and Bm showed a therapeutic effect against AlM toxicity; however, it was found that the therapeutic potential of BPC was more pronounced than Bm against AlM-induced neurotoxicity.

Background: Aluminum is a potent environmental toxin and its increasing entry exposes human beings to its neurotoxicity. Objective: The authors investigated the efficacy of delivery systems (magnesium oxide nanoparticles [MgONPs] and solid lipid nanoparticles [SLNs]) for curcumin in protecting aluminum-induced neurotoxicity in albino rats. Materials and Methods: Albino rats were divided into six groups (n = 6), Group I served as control; Group II Al treated; Group III curcumin loaded MgONPs (CuMgONPs); Group IV Al + CuMgONPs; Group V curcumin loaded SLNs (CuSLNs); Group VI Al + CuSLNs. After the treatment period, i.e., 30 days the animals were sacrificed and biochemical tests were performed to assess the cholinergic damage followed by histological observation of brain regions (cerebral cortex and cerebellum). Results: In cholinergic analyses, it was observed that aluminum-induced alterations in ACh and acetylcholine esterase were reversed with concomitant administration of CuMgONPs and CuSLNs. The therapeutic potential of CuMgONPs and CuSLNs was also observed in histological analyses of brain regions treated with aluminum. Among these two drug delivery systems, CuSLNs administration was found to be more potential compared to the CuMgONPs in treating aluminum induced neurotoxicity. Conclusions: By using drug delivery systems, MgONPs and SLNs, the problem of low bioavailability of curcumin can be controlled. This will be a promising agent to treat neurodegenerative disorders such as Alzheimer's disease with the potentiality to cross the blood–brain barrier. However, CuSLNs has showed a more protective effect on altered cholinergic system and tissue damage compared to CuMgONPs.

The concentration variation of Ho3+ ion-doped SiO2–Al2O3–Na2CO3–SrF2–CaF2 glasses has been prepared by conventional melt quenching method. The thermal stability of 1 mol % of Ho3+-doped oxyfluorosilicate glass has been calculated using the differential thermal analysis (DTA) spectra. The phenomenological Judd–Ofelt intensity parameters Ωλ (λ = 2, 4 and 6) were calculated for all concentrations of Ho3+ ions. The luminescence spectra in visible region of Ho3+ ion-doped glasses were recorded under the excitation wavelength of 452 nm. The spectra consists of several intense emission bands (5F4, 5S2) → 5I8 (547 nm), 5F3 → 5I8 (647 nm), 5F5 → 5I7 (660 nm) and (5F4, 5S2) → 5I7 (750 nm) in the range 500–780 nm. The fluorescence emission at ∼2.0 µm (5I7 → 5I8) was observed under the excitation of 488 nm Ar-ion laser. The stimulated emission cross section for 5I7 → 5I8 transition (∼2.0 µm) varies from 8.46 to 9.52 × 10−21 cm2, as calculated by the Fuchtbauer–Ladenburg (FL) theory. However, Mc-Cumber theory was used to calculate emission cross section values about 4.24–5.75 × 10−21 cm2 for the 5I7 → 5I8 transition in all concentrations of Ho3+-doped oxyfluorosilicate glasses. Therefore, these results reveal that the 0.5 mol % of Ho3+-doped oxyfluorosilicate glasses, exhibiting higher emission cross section, has potentially been used for laser applications at ∼ 2.0 µm.

Objective The aim of the present study is to investigate the antioxidant potentiality of Bacopa monniera through the synthesized gold nanoparticles (BmGNPS). The antioxidant activity of BmGNPS was evaluated in mice by assessing the oxidative stress induced by aluminum. Method Male albino mice were randomly divided into five groups. First group was treated as control, second group received aluminum acetate (5 mg/kg b.w), third group received B. monniera extract (5 mg/kg b.w), fourth group received BmGNPs (5 mg/kg b.w), fifth group received aluminum acetate plus BmGNPs. The lipid peroxidation (TBA-RS) levels and antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidise (GPx) activities were estimated in brain, liver and kidney of albino mice. Results and discussion Exposure to Aluminum acetate (Al) significantly increased the lipid peroxidation (TBA-RS) levels, with a significant decrease in the antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidise (GPx) activities, which may be due to the oxidative stress induced by the release of free radicals. No significant changes were observed in the BmGNPs alone treated mice when compared to control, whereas synchronous administration of BmGNPs to Al treated mice showed a significant decrease in TBA-RS levels and increase in SOD, CAT and GPx activities these results reveals the potential free radical scavenging property of BmGNPs. Conclusion This study suggests that the BmGNPs has the ability in counteracting Al induced oxidative stress in male albino mice.

The Yb 3+ and Yb 3+ /Nd 3+ co-doped SiO2-Al2O3-Na2CO3-SrF2-CaF2 oxyfluorosilicate glasses have been prepared by high temperature melt-quenching method. The prepared glasses are excited with 808 nm, and the near infrared emission bands are observed. The intensified emission band was centered at 1030 nm ( 2 F 5/2 -> 2 F 7/2 ) of Yb 3+ ions. Stimulated emission cross-section was evaluated for the prominent 2 F 5/2 -> 2 F 7/2 transition of Yb 3+ ion by using the Mc-Cumber theory. The energy transfer from Nd 3+ to Yb 3+ ions in co-doped silicate based oxyfluoride glasses are described under the 514 nm excitation wavelength. Full Text: PDF References N. Chiodini, A. Paleari, G. Brambilla, E. R. Taylor, "Erbium doped nanostructured tin?silicate glass?ceramic composites", Appl. Phys. Lett. 80, 4449 (2002). CrossRef D. Jaque, J. Capmany, F. Molero, Z. D. Luo, J. G. Sole, "Up-conversion luminescence in the Nd 3+ :YAB self frequency doubling laser crystal", Opt. mater. 10, 211 (1998). CrossRef H. Lin, G. Meredith, S. Jiang, X. Peng, T. Luo, N. Peyghambarian, E. Yue-Bun Pun, "Optical transitions and visible upconversion in Er 3+ doped niobic tellurite glass", J. Appl. Phys. 93, 186 (2003) CrossRef Atul D. Sontakke, K. Annapurna, "Phonon assisted effective non-resonant energy transfer based 1 ?m luminescence from Nd 3+ ?Yb 3+ codoped zinc?boro?bismuthate glasses", J. Lumin. 138, 229 (2013). CrossRef F. Liegard, J.L. Doualan, R. Moncorge, M. Bettinelli, "Nd 3+ ? Yb 3+ energy transfer in a codoped metaphosphate glass as a model for Yb 3+ laser operation around 980 nm", Appl. Phys. B 80, 985 (2005) CrossRef A. Miguel, B. Fan, R. Balda, X. Zhang, J. Fernandez, J.L. Adam, "Spectroscopy and energy transfer in Nd 3 + /Yb 3 + codoped chalcohalide glasses", J. Non-Cryst. Solids 377, 110 (2013). CrossRef G. Devarajulu, B. Deva Prasad Raju, "Effect of concentration variation on 2.0 ?m emission of Ho 3+ -doped SiO 2 ?Al 2 O 3 ?Na 2 CO 3 ?SrF 2 ?CaF 2 oxyfluorosilicate glasses", App. Phy. A, 124 (2018). CrossRef Radoslaw Lisiecki, Elzbiecta Augustyn, Witold Ryba-Romanowski, Michal Zelechower, "Er-doped and Er, Yb co-doped oxyfluoride glasses and glass?ceramics, structural and optical properties", Opt. Mater. 33, 1630 (2011). CrossRef G. Chen, Q. Zhang, G. Yang, and Z. Jiang, "Mid-Infrared Emission Characteristic and Energy Transfer of Ho 3+ -Doped Tellurite Glass Sensitized by Tm 3+ ", J. Fluoresc. 17, 301 (2007). CrossRef D. E. McCumber, "Theory of Phonon-Terminated Optical Masers", Phys. Rev. 134, 299 (1964). CrossRef D.L. Deloach, S.A. Payne, L.K. Smith, W.L. Kway, W. F. Krupke, "Laser and spectroscopic properties of Sr 5 (PO 4 ) 3 F:Yb", J. Opt. Soc. Am. B 11, 269 (1994). CrossRef K. Venkata Krishnaiah, R. Rajeswari, K. UpendraKumar, S. Surendra Babu, I.R. Martin, C.K. Jayasankar, "Spectroscopy and radiation trapping of Yb 3+ ions in lead phosphate glasses", J.Quant. Spect. Rad. Trans. 140, 37 (2014). CrossRef